Amphibalunus subalbidus (Henry, 1973)

(Figs 8 a –h)

Material examined. ZUTC-cirri 1187. Persian Gulf. First record from the Persian Gulf.

Gulf of Oman. No record.

General distribution and habitat. Western Atlantic and Gulf of Mexico, oligo-mesohaline in estuaries, on various substrata in the intertidal zone (Henry & McLaughlin 1975; Dineen & Hines 1994).

Descriptive features and remarks. Shell conic to nearly cylindrical, often smooth, white (Fig. 8 h), sheath vesicular (Fig. 8 e). Tergum (Figs 8 a, b) and scutum (Figs 8 c, d) white, growth ridges of scutum not prominent. Labrum with 13 teeth on each side of notch (Fig. 8 g). Mandible with five teeth. First maxilla without notch, five small spines between upper and lower pairs of large spines. CI 14-segmented, anterior ramus slightly longer than posterior (12-segmented). CII and CIII with anterior ramus more or less longer than posterior ramus. Cirrus IV with erect tooth at postero-distal angle of segments absent (Fig. 8 f). Largest specimen with basal diameter 12.9 mm, height 10.2 mm.

Specimens were collected from the Arvandroud River (30° 19′N, 48° 17E), Karoon River (30° 26′N, 48° 12′E), Bahmanshir River (30° 09′N, 48° 35′E) and Zohre River (30° 04′N 49° 33′E) (Fig. 1). The present specimens were observed on various substrata including ship and vessel hulls in fishing ports, jetties, reed stems, stones and mollusc shells, and in salinities ranging from 1.6 ppt (Karoon River) to 17.8 ppt (Arvandroud River).